In honor of Earth Day, PBS's "Independent Lens" features Revenge of the Electric Car April 19, at 10 p.m. The filmmakers spent three years tracing the real reasons – and players – behind the demise of General Motors' plug-in EV1 and tracking the return of today's electric car market.

In the wake of director James Cameron setting a record for deepest solo dive, a video by National Geographic sheds light on his experience, including footage of him emerging safely from the sub, video of the desolate ocean floor, and an interview about the dive. At one point, he says the pressure on the sub was so great that it caused the sides to compress by three inches – with him inside, of course. Check out the video at nationalgeographic.com and search for Cameron solo dive.

'Once' more

Once, the musical based on the hit 2007 Sundance Film Festival selection about a busker and an immigrant, has a lilting, fresh, indie musical soundtrack. Now available on CD, this recording features the original Broadway cast. Hansard and Irglová's song "Falling Slowly" received a 2007 Academy Award for Best Original Song, and the soundtrack as a whole also received a Grammy nomination.

Take a ride on the Salmon River, deep in the heart of Idaho's Frank Church – River of No Return Wilderness, home to everything from otters to elk, deer, bluebirds, and nine packs of wolves that are being reintroduced after a 50-year absence. The wilderness is larger than Yellowstone National Park, yet few people have heard of it, let alone visited it. River of No Return, on PBS's "Nature" April 18 at 9 p.m. ventures into the wilderness's rugged mountains for a rare visit.